1. Field of the Invention
The invention relates to a matrix printer comprising a combination of a carriage and a printing head which is mounted thereon, said combination being movable to and fro along a paper guide, said printing head having a first printing position for printing character elements during a pass from left to right and a second printing position for printing character elements during a pass from right to left, the character elements of a given printing element in the printing head printed on the paper during the movement of the printing head to the right being displaced over a distance which amounts to a part of the vertical distance between two successive printing elements in the printing head with respect to the character elements of the same printing element printed on the paper during the movement to the left.
2. Description of the Prior Art
In a known matrix printer of the kind set forth (U.S. Pat. No. 4,086,997), the height of the printing head with respect to the paper guide is adjusted by actuation of an electromagnet whose armature is connected, via a lever, to an eccentric, which cooperates with a part of the longitudinal guide of the carriage. The height adjustment of the printing head is realized by pivoting of the printing head about an axis which extends parallel to the line direction. Because the height of the printing head can be adjusted as desired, a choice is possible between characters whose constituent elements (dots) are situated comparatively far apart and characters whose constituent elements are situated comparatively near to one another or which even overlap one another.
For many applications, however, it is necessary that the constituent elements of the printed character are always situated comparatively near to one another or overlap one another. This is the case, for example, in so-called text editing machines. Even though an electromagnetic height adjustment of the printing head could be used in such applications, a height adjustment of this kind is comparatively expensive because the facility offered is greater than required, i.e. adjustment as desired.